In Contra Costa County there are 4 residential Fiber providers covering 57.01% of the county. The average home can get speeds up to 6,264 Mbps. Note that we may have a financial relationship with some of the providers below. This does not influence rankings, and helps us provide high-quality detailed information for free.
This page contains all Fiber internet providers in Contra Costa County, CA.
To see availability maps for all providers including fiber, cable, DSL, and more in Contra Costa County, CA please click below.
Contra Costa County, CA Availability Maps
Fiber Internet Service Providers in Contra Costa County
Data updated 11/14/2025, based on FCC data from 12/31/2024. This is the most current data available as of .
To avoid wasting your time, providers with less than 1% coverage in Contra Costa County are not shown.
Contra Costa County Satellite TV & Internet Providers
DISH Satellite TV
DIRECTV Satellite TV
Not sure whether to choose Dish or DIRECTV? For most people most of the time we recommend DISH. But click here to learn more.
Viasat Satellite Internet
Where in Contra Costa County is fiber internet available?
Fiber Internet Availability Key
Fiber is available in 57.01% of Contra Costa County. Areas in green have fiber internet service, where areas in yellow or red may not. The most widely available provider is AT&T. Call one of the companies with service in Contra Costa County above to see who has service at your home.
How fast is fiber internet in Contra Costa County?
The map below shows maximum fiber internet speeds by area in Contra Costa County.
Fiber Internet Speed Key
The average Contra Costa County home can get up to 6,264 Mbps on their fiber internet plan. The fastest fiber download speed in the county is 10,000 Mbps, which 18.89% of residents can get. Some homes and apartments do not have access to these speeds. On the slower end, for example, less than 1% of homes can only purchase plans up to 50 Mbps. See the internet provider details below for info about their speed and coverage in Contra Costa County.
Fiber internet speeds tend to be faster in the west parts of Contra Costa County, and slower in the east areas of the county.
Is fiber the fastest internet I can get in Contra Costa County?
The fastest internet for you may vary based on where in Contra Costa County you live. In general, cable competes most often with fiber in the county.
- Fiber is the fastest internet type for 51.31% of Contra Costa County homes.
- Cable is fastest for 48.05% of the county.
- DSL is fastest for less than 1%.
- Fixed wireless is fastest for less than 1%.
- Satellite internet may be the only option for less than 1% of Contra Costa County homes.
Fiber Providers in Depth
Below you'll find which TV and internet providers offer service in Contra Costa County, along with details on where in Contra Costa County and at what speeds.
EarthLink Fiber in Contra Costa County, CA
EarthLink fiber coverage
About 50.49%, or 588,648 people, have EarthLink fiber internet available to them in the county. The company covers the entire Contra Costa County area. EarthLink is one of the largest internet service providers internet service providers in the US, with internet service available in a majority of Contra Costa County.
EarthLink fiber download speeds
EarthLink is above average when comparing download speeds to all other internet providers in Contra Costa County. Versus other fiber providers in the area, EarthLink fiber is above average. There are 3 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from EarthLink goes up to 5,000 Mbps, the slowest package only goes up to 50 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 4,653 Mbps.
Show all download speeds
- 91.3% up to 5,000.0 Mbps
- 8.6% up to 1,000.0 Mbps
- 0.1% up to 50.0 Mbps
EarthLink fiber upload speeds
In Contra Costa County download speeds tend to be equal to than upload speeds for EarthLink fiber. Compared to other ISPs, EarthLink is above average where upload speeds are concerned, and above average compared to other Contra Costa County fiber providers. EarthLink offers 3 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County is up to 5,000 Mbps. Some customers have slower plan choices, which only go up to 50 Mbps. On average, EarthLink customers can get speeds up to 4,653 Mbps.
Show all upload speeds
- 91.3% up to 5,000.0 Mbps
- 8.6% up to 1,000.0 Mbps
- 0.1% up to 50.0 Mbps
AT&T Fiber in Contra Costa County, CA
AT&T fiber coverage
About 50.49%, or 588,648 people, have AT&T fiber internet available to them in the county. The company covers the entire Contra Costa County area. AT&T is one of the largest internet service providers internet service providers in the US, with internet service available in a majority of Contra Costa County.
AT&T fiber download speeds
AT&T is above average when comparing download speeds to all other internet providers in Contra Costa County. Versus other fiber providers in the area, AT&T fiber is above average. There are 3 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from AT&T goes up to 5,000 Mbps, the slowest package only goes up to 50 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 4,653 Mbps.
Show all download speeds
- 91.3% up to 5,000.0 Mbps
- 8.6% up to 1,000.0 Mbps
- 0.1% up to 50.0 Mbps
AT&T fiber upload speeds
In Contra Costa County download speeds tend to be equal to than upload speeds for AT&T fiber. Compared to other ISPs, AT&T is above average where upload speeds are concerned, and above average compared to other Contra Costa County fiber providers. AT&T offers 3 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County is up to 5,000 Mbps. Some customers have slower plan choices, which only go up to 50 Mbps. On average, AT&T customers can get speeds up to 4,653 Mbps.
Show all upload speeds
- 91.3% up to 5,000.0 Mbps
- 8.6% up to 1,000.0 Mbps
- 0.1% up to 50.0 Mbps
Sonic Fiber in Contra Costa County, CA
Sonic fiber coverage
About 23.31%, or 271,780 people, have Sonic fiber internet available to them in the county. The company covers the west, southwest, south, east, north, northwest, central, and southeast Contra Costa County area. Sonic is a large internet service provider internet service providers in the US, with internet service available in a small portion of Contra Costa County.
Sonic fiber download speeds
Sonic is the fastest when comparing download speeds to all other internet providers in Contra Costa County. Versus other fiber providers in the area, Sonic fiber is the fastest. There are 2 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from Sonic goes up to 10,000 Mbps, the slowest package only goes up to 1,000 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 8,293 Mbps.
Show all download speeds
- 81.0% up to 10,000.0 Mbps
- 19.0% up to 1,000.0 Mbps
Sonic fiber upload speeds
In Contra Costa County download speeds tend to be equal to than upload speeds for Sonic fiber. Compared to other ISPs, Sonic is the fastest where upload speeds are concerned, and the fastest compared to other Contra Costa County fiber providers. Sonic offers 2 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County is up to 10,000 Mbps. Some customers have slower plan choices, which only go up to 1,000 Mbps. On average, Sonic customers can get speeds up to 8,293 Mbps.
Show all upload speeds
- 81.0% up to 10,000.0 Mbps
- 19.0% up to 1,000.0 Mbps
Astound Broadband Fiber in Contra Costa County, CA
Astound Broadband fiber coverage
About 3.61%, or 42,093 people, have Astound Broadband fiber internet available to them in the county. The company covers the north, northwest, south, and central Contra Costa County area. Astound Broadband is one of the largest internet service providers internet service providers in the US, with internet service available in a very small piece of Contra Costa County.
Astound Broadband fiber download speeds
Astound Broadband is above average when comparing download speeds to all other internet providers in Contra Costa County. Versus other fiber providers in the area, Astound Broadband fiber is the slowest. There are 2 different maximum speeds throughout Contra Costa County. The fastest plan anyone in Contra Costa County can order from Astound Broadband goes up to 5,000 Mbps, the slowest package only goes up to 1,500 Mbps, and the county-wide average maximum speed for Contra Costa County customers is up to 1,500 Mbps.
Show all download speeds
- 0.0% up to 5,000.0 Mbps
- 100.0% up to 1,500.0 Mbps
Astound Broadband fiber upload speeds
In Contra Costa County download speeds tend to be equal to than upload speeds for Astound Broadband fiber. Compared to other ISPs, Astound Broadband is above average where upload speeds are concerned, and below average compared to other Contra Costa County fiber providers. Astound Broadband offers 2 different upload speeds across the county, so your internet plan's upload speed may vary by neighborhood . The fastest upload speed available to anyone from this ISP in Contra Costa County is up to 5,000 Mbps. Some customers have slower plan choices, which only go up to 1,500 Mbps. On average, Astound Broadband customers can get speeds up to 1,500 Mbps.
Show all upload speeds
- 0.0% up to 5,000.0 Mbps
- 100.0% up to 1,500.0 Mbps
Contra Costa County Fiber by Area
This information is most helpful to those looking for homes or considering moving to Contra Costa County or any of the areas nearby.
How does fiber internet in Contra Costa County compare to the rest of California?
Fiber internet speeds in Contra Costa County are much faster versus the average speeds in California: 0.00 Mbps in California versus 6,264 Mbps in the county. The state has similar fiber availability compared to the county. Average fiber coverage in California is 0.00% versus 57.01% in Contra Costa County.
What zip codes have fiber internet?
Fiber internet coverage varies by zip code and neighborhood. Some examples in or around Contra Costa County are shown below. You can enter any zip code here to see TV and internet providers by zip code.
What does fiber internet look like in other counties?
Below are counties nearby and with similar populations. This comparison can be useful if living somewhere with fast internet is important to you.
Nearby Counties
- Marin County, CA: more fiber coverage, slower speeds
- San Joaquin County, CA: less fiber coverage, slower speeds
- Tuolumne County, CA: less fiber coverage, slower speeds
- San Miguel County, CO: less fiber coverage, slower speeds
- San Juan County, CO: more fiber coverage, slower speeds
- Hinsdale County, CO: more fiber coverage, slower speeds
- Saguache County, CO: less fiber coverage, slower speeds
- Otero County, CO: less fiber coverage, slower speeds
- Bent County, CO: more fiber coverage, slower speeds
- Prowers County, CO: less fiber coverage, slower speeds
Counties with Similar Populations
- Santa Clara County, CA: less fiber coverage, slower speeds
- Wayne County, MI: less fiber coverage, slower speeds
- Honolulu County, HI: more fiber coverage, slower speeds
- Travis County, TX: more fiber coverage, slower speeds
- Suffolk County, NY: more fiber coverage, faster speeds
- Palm Beach County, FL: more fiber coverage, slower speeds
- Oakland County, MI: less fiber coverage, slower speeds
- Philadelphia County, PA: more fiber coverage, slower speeds
- Pima County, AZ: less fiber coverage, slower speeds
- Broward County, FL: more fiber coverage, slower speeds